Method for measuring quiescent current in a switching voltage regulator

Abstract

One example includes a method for measuring a quiescent current in a switching voltage regulator. The method includes generating a mathematical model of a circuit design associated with the switching voltage regulator. The mathematical model includes measurable parameters to describe a switching current of a power switch of the switching voltage regulator. The method also includes fabricating a circuit comprising the switching voltage regulator based on the circuit design. The fabricated circuit includes the power switch and conductive I/O. The method also includes coupling the conductive I/O of the fabricated circuit to a circuit test fixture and providing electrical signals to the conductive I/O via the circuit test fixture. The method also includes measuring the measurable parameters in response to the electrical signals and applying the measurable parameters to the mathematical model to calculate the switching current. The method further includes calculating the quiescent current based on the switching current.

What is claimed is: 
     
       1. A method for measuring a quiescent current in a switching voltage regulator, the method comprising:
 generating a mathematical model of a circuit design associated with the switching voltage regulator, the mathematical model comprising measurable parameters to describe a switching current associated with a power switch of the switching voltage regulator; 
 fabricating a circuit comprising the switching voltage regulator based on the circuit design, the fabricated circuit comprising the power switch and conductive inputs/outputs (I/O); 
 coupling the conductive I/O of the fabricated circuit to a circuit test fixture; 
 providing electrical signals to the conductive I/O via the circuit test fixture; 
 measuring the measurable parameters in response to the electrical signals; 
 applying the measurable parameters to the mathematical model to calculate the switching current; and 
 calculating the quiescent current based on the switching current. 
 
     
     
       2. The method of  claim 1 , wherein the mathematical model describes an average switching current associated with the switching voltage regulator. 
     
     
       3. The method of  claim 1 , wherein the conductive I/O comprises:
 a first lead adapted to be coupled to an inductor; and 
 a second lead adapted to be coupled to a capacitor; 
 
       wherein measuring the measurable parameters comprises:
 measuring a peak switching current based on the electrical signals provided to the first and second leads; 
 measuring a threshold associated with a capacitor voltage at the second lead based on the electrical signals provided to the first and second leads; and 
 measuring internal operational currents of the switching voltage regulator. 
 
     
     
       4. The method of  claim 3 , wherein providing the electrical signals comprises providing a current ramp to the first lead, wherein measuring the peak switching current comprises:
 monitoring a switching voltage at the first lead to determine a change in the switching voltage indicative of deactivation of the power switch; and 
 measuring the peak switching current corresponding to a magnitude of the current ramp at which the power switch deactivates. 
 
     
     
       5. The method of  claim 3 , wherein providing the electrical signals comprises:
 providing a voltage at a first magnitude at the second lead; 
 gradually increasing the voltage from the first magnitude at a positive slope ramp; 
 
       wherein measuring the peak switching current comprises:
 monitoring a current at the first lead to determine deactivation of the power switch; and 
 measuring a maximum capacitor voltage corresponding to the voltage at the second lead in response to determining the deactivation of the power switch. 
 
     
     
       6. The method of  claim 3 , wherein providing the electrical signals comprises:
 providing a voltage at a first magnitude at the second lead; 
 gradually decreasing the voltage from the first magnitude at a negative slope ramp; 
 
       wherein measuring the peak switching current comprises:
 monitoring a current at the first lead to determine activation of the power switch; and 
 measuring a minimum capacitor voltage corresponding to the voltage at the second lead in response to determining the activation of the power switch. 
 
     
     
       7. The method of  claim 3 , wherein the conductive I/O further comprises a third lead adapted to be coupled to a supply voltage; 
       wherein providing the electrical signals comprises:
 providing a first voltage at the third lead; and 
 providing a second voltage relative to the first voltage at the second lead; 
 
       wherein measuring internal operational currents of the switching voltage regulator comprises measuring the internal operational currents of the switching voltage regulator based on currents associated with each of the first and second voltages. 
     
     
       8. The method of  claim 7 , wherein calculating the quiescent current comprises calculating the quiescent current based on an average switching current and the internal operational currents associated with the mathematical model. 
     
     
       9. The method of  claim 1 , wherein the switching voltage regulator is a boost switching voltage regulator. 
     
     
       10. A method for measuring a quiescent current in a boost switching voltage regulator, the method comprising:
 generating a mathematical model of a circuit design associated with the boost switching voltage regulator, the mathematical model comprising measurable parameters to describe an average switching current and internal operational currents associated with a power switch of the boost switching voltage regulator; 
 fabricating a circuit comprising the boost switching voltage regulator based on the circuit design, the fabricated circuit comprising the power switch and conductive inputs/outputs (I/O); 
 coupling the conductive I/O of the fabricated circuit to a circuit test fixture; 
 providing electrical signals to the conductive I/O via the circuit test fixture; 
 measuring the measurable parameters in response to the electrical signals; 
 applying the measurable parameters to the mathematical model to calculate the average switching current; and 
 calculating the quiescent current based on the average switching current and the internal operational currents associated with the mathematical model. 
 
     
     
       11. The method of  claim 10 , wherein the conductive I/O comprises:
 a first lead adapted to be coupled to an inductor; and 
 a second lead adapted to be coupled to a capacitor; 
 
       wherein measuring the measurable parameters comprises:
 measuring a peak switching current based on the electrical signals provided to the first and second leads; 
 measuring a threshold associated with a capacitor voltage at the second lead based on the electrical signals provided to the first and second leads; and 
 measuring internal operational currents of the switching voltage regulator. 
 
     
     
       12. The method of  claim 11 , wherein providing the electrical signals comprises providing a current ramp to the first lead, wherein measuring the peak average switching current comprises:
 monitoring a switching voltage at the first lead to determine a change in the switching voltage indicative of deactivation of the power switch; and 
 measuring the peak average switching current corresponding to a magnitude of the current ramp at which the power switch deactivates. 
 
     
     
       13. The method of  claim 11 , wherein providing the electrical signals comprises:
 providing a voltage at a first magnitude at the second lead; 
 gradually increasing the voltage from the first magnitude at a positive slope ramp; 
 
       wherein measuring the peak switching current comprises:
 monitoring a current at the first lead to determine deactivation of the power switch; and 
 measuring a maximum capacitor voltage corresponding to the voltage at the second lead in response to determining the deactivation of the power switch. 
 
     
     
       14. The method of  claim 11 , wherein providing the electrical signals comprises:
 providing a voltage at a first magnitude at the second lead; 
 gradually decreasing the voltage from the first magnitude at a negative slope ramp; 
 
       wherein measuring the peak switching current comprises:
 monitoring a current at the first lead to determine activation of the power switch; and 
 measuring a minimum capacitor voltage corresponding to the voltage at the second lead in response to determining the activation of the power switch. 
 
     
     
       15. The method of  claim 11 , wherein the conductive I/O further comprises a third lead adapted to be coupled to a supply voltage;
 wherein providing the electrical signals comprises:
 providing a first voltage at the third lead; and 
 providing a second voltage relative to the first voltage at the second lead; 
 
 wherein measuring internal operational currents of the switching voltage regulator comprises measuring the internal operational currents of the switching voltage regulator based on currents associated with each of the first and second voltages. 
 
     
     
       16. A method for measuring a quiescent current in a switching voltage regulator, the method comprising:
 generating a mathematical model of a circuit design associated with the switching voltage regulator, the mathematical model comprising measurable parameters to describe an average switching current associated with a power switch of the switching voltage regulator, the measurable parameters comprising a peak switching current, a capacitor voltage, and internal operational currents of the switching voltage regulator; 
 fabricating a circuit comprising the switching voltage regulator based on the circuit design, the fabricated circuit comprising the power switch, a first lead adapted to be coupled to an inductor, and a second lead adapted to be coupled to a capacitor; 
 coupling the first and second leads of the fabricated circuit to a circuit test fixture; 
 providing electrical signals to the first and second leads via the circuit test fixture; 
 measuring the measurable parameters in response to the electrical signals; 
 applying the measurable parameters to the mathematical model to calculate the average switching current; and 
 calculating the quiescent current based on the average switching current and the internal operational currents associated with the mathematical model. 
 
     
     
       17. The method of  claim 16 , wherein providing the electrical signals comprises providing a current ramp to the first lead, wherein measuring the peak switching current comprises:
 monitoring a switching voltage at the first lead to determine a change in the switching voltage indicative of deactivation of the power switch; and 
 measuring the peak switching current corresponding to a magnitude of the current ramp at which the power switch deactivates. 
 
     
     
       18. The method of  claim 16 , wherein providing the electrical signals comprises:
 providing a voltage at a first magnitude at the second lead; 
 gradually increasing the voltage from the first magnitude at a positive slope ramp; 
 
       wherein measuring the peak switching current comprises:
 monitoring a current at the first lead to determine deactivation of the power switch; and 
 measuring a maximum capacitor voltage corresponding to the voltage at the second lead in response to determining the deactivation of the power switch. 
 
     
     
       19. The method of  claim 16 , wherein providing the electrical signals comprises:
 providing a voltage at a first magnitude at the second lead; 
 gradually decreasing the voltage from the first magnitude at a negative slope ramp; 
 
       wherein measuring the peak switching current comprises:
 monitoring a current at the first lead to determine activation of the power switch; and 
 measuring a minimum capacitor voltage corresponding to the voltage at the second lead in response to determining the activation of the power switch. 
 
     
     
       20. The method of  claim 16 , wherein the fabricated circuit further comprises a third lead adapted to be coupled to a supply voltage;
 wherein providing the electrical signals comprises:
 providing a first voltage at the third lead; and 
 providing a second voltage relative to the first voltage at the second lead; 
 
 wherein measuring internal operational currents of the switching voltage regulator comprises measuring the internal operational currents of the switching voltage regulator based on currents associated with each of the first and second voltages.